FILE - In this June 5, 2017, file photo, Donald Trump Jr., executive vice president of The Trump Organization, announces that the family's company is launching a new hotel chain inspired by his and brother Eric's Trump's travels with their father's campaign at Trump Tower in New York. Trump Jr. shared a video on July 8, 2017, of an edited clip of the 1986 military thriller “Top Gun” in which President Donald Trump’s face is superimposed over Tom Cruise’s character as he shoots down a Russian jet with a CNN logo on it. (AP Photo/Kathy Willens, File)

WASHINGTON (AP) – The chairman of the Senate Judiciary Committee says he’s sending a letter to Donald Trump Jr. to ask him to testify.

Sen. Chuck Grassley says he’d subpoena the president’s eldest son if necessary. The Iowa Republican says he wants Trump Jr. to appear “pretty soon,” and it could be as early as next week.

Trump Jr. released emails this week from 2016 in which he appeared eager to accept information from the Russian government that could have damaged Hillary Clinton’s campaign.

The panel is investigating Russian meddling in the U.S. election. Grassley wouldn’t say what he wants to hear from the president’s eldest son, but said members aren’t restricted “from asking anything they want to ask.”